February 14, 2012

‘Invisibility’ Cloak For Buildings No Longer Just Sci-Fi

by editor

A group of British researchers has been hard at work attempting to bring a seemingly kooky, outlandish idea into the realm of the real. Their work has focused on attempting to create a proverbial invisibility cloak that would enable engineers to ℠hide´ buildings from earthquake tremors and other destructive forces.

Once the exclusive territory of science-fiction, scientists have explored the theory of ℠cloaking´ in a variety of contexts and fields in recent years. One of the more promising of these has been carried out by a team of researchers at University of Manchester´s School of Mathematics led by Dr. William Parnell.

Writing in the prestigious journal the Proceedings of the Royal Society A, Parnell´s team has demonstrated that a special grade of pressurized rubber can be used to protect the infrastructure of buildings from the damaging shock waves that follow natural disasters such as earthquakes.

In their paper, the researchers describe how the structural properties of the rubber allow waves to simply pass around structures, leaving them undamaged and intact. From the perspective of the wave, it´s as though the objects simply weren´t there.

In the wake of last year´s Fukushima Daiichi nuclear disaster, such a protective technology could prove a decisive factor for the future of the nuclear power industry.

But the implications and potential uses for Parnell´s variety of cloaking don´t stop at nuclear reactors. The ℠invisibility´ function could also be used to safeguard a variety of vulnerable financial buildings as well as electric pylons, dams and other critical structures from natural or man-made attacks.

This research is just one example from a growing field of research looking into the possibilities of cloaking technology. And most of these focus on making objects virtually transparent to various forms of wave whether sound, light or vibration.

The first work in the field began some six years ago when a handful of research groups around the world began looking into the tricky task of cloaking objects from light waves. Interestingly, research into cloaking from vibration waves has been simultaneously one of the most recent and–as Parnell´s study indicates–successful of these scientific ventures.

As Parnell pointed out to the University of Manchester´s online news site, scientific technology is quickly catching up with the imagination of science fiction authors.

“Significant progress has been made, both theoretically and practically in the area of cloaking. Five or six years ago scientists started with light waves, and in the last few years we have started to consider other wave-types, most importantly perhaps sound and elastic waves,” he explained.

“The real problem with the latter is that it is normally impossible to use naturally available materials as cloaks. [“¦] We showed theoretically that pre-stressing a naturally available material — rubber — leads to a cloaking effect from a specific type of elastic wave,” he added.

Parnell believes that his team´s research has opened up a world of possibilities for manipulating the speed and direction elastic waves. Now, he says, his group will focus on expanding the success of their research in an attempt to construct a general theory for vibration cloaking.

“This is important because we want to guide such waves in many contexts, especially in nano-applications such as in electronics for example,” he explained.

“If the theory can be scaled up to larger objects then it could be used to create cloaks to protect buildings and structures, or perhaps more realistically to protect very important specific parts of those structures.”